The Evolution of Oracle Change Data Capture

 Let us start by understanding the concept behind Oracle Change Data Capture. 

Change Data Capture (CDC) is a software pattern that tracks all changes made to the source database, which can then be monitored and action taken based on the records of these changes. With CDC, users integrate data by identifying, capturing, and delivering changes made to a source business database.  

The Oracle Change Data Capture feature was introduced with the 9i version out of the box. Its goal was to track and record changes made to databases in user tables that were then stored in change tables. These changes were then processed and moved to databases and data warehouses by the Extract, Transform, and Load (ETL) application. 

However, this technology was not well-received by DBAs as it adversely impacted the performance of databases. This was because triggers were placed in the source database that were set off whenever a change was tracked, a complex process that required repeated refreshes of databases. 


Based on this feedback, this Oracle Change Data Capture was modified, and a new version of CDC named Oracle Streams was introduced with the 10g version, which was a great success and a radical improvement over the previous version. It used the redo logs of the source database along with the replication tool of Oracle, which is also a built-in feature. 

This form of Oracle Change Data Capture could track changes made at the source database and transfer them to the target database without lowering the source system’s speed or performance.  

While this technology and feature appealed to users, Oracle surprisingly discontinued Oracle Streams from its 12c version. Users who wanted to use the Oracle Change Data Capture had two options: use a third-party application or pay for Oracle Golden Gate.     

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